Hi ther all....I use Shell / Racetrack gas only at various stations throughout mid / northern Louisiana except for 1 tankfull at a podunk no name in the boonies and here's the rest of the story..
03 Taurus with Vulcan engine and 62k miles..regular maintenance at Ford..
at 45,000 miles taurus coughed and killed on interstate Ford Ford ran DTC
diagnostics called the P0191 Fuel Rail Pressure code ...replaced fuel filter much brown gunk out of input side of filter...ran fine 2 months..
55,000 coughed again on interstate took back to Ford replaced fuel filter again P0191 code ran fine for 1 month until it got down to 1/2 tank of fuel so I kept it full..
last week at 62,000 miles started running rough again replaced fuel filter..no junk in filter..still runs bad...until I stop the car , then restart runs fine for a 5 minutes or 15 minutes at 75 mph or sometimes will killl at a stopsign
had service tech at local shop (ford store backed up for 3 days) check fuel pressure after P0191 code with mac tech tool reading as high as 45 psi
as low as 7psi fuel pressure when reving the engine...tech say NO question BAD FUEL PUMP..($650 to R and R tank and pump) i say why not a faulty pressure regulator with a leaking diaphragm??
seems to me an electric motor either works or it doesn't??
your advice and help help PLEASE!!
walt in baton rouge 225 753 9455